IADR Abstract Archives

Potentional environmental impacts arising from mercury-free dental materials

Objectives Mercury-free dental materials have seen greater use in dentistry due to the Minamata Convention and due in part to Article 10 of Regulation (EU) 2017/852 restricting the use of dental amalgam in certain patient categories. Furthermore, the discharge of mercury waste and wastewater is strictly regulated by requiring each clinic to be equipped with an amalgam separator that is at least 95% efficient in removing dental amalgam particles from wastewater. In this study we assess the utility of these amalgam separators to also remove particles resulting from the use of mercury-free dental filling materials by carrying out testing in three different dental clinics. Methods A range of analytical chemistry methods was applied in order to obtain results of particle quantities, as well as particle shape and size using light and scanning electron microscopy. Environmental impacts were assessed by conducting OECD 202 standardised acute immobilisation tests on the small planktonic crustacean Daphnia magna. Results Analysis of the wastewater resulting from the use of mercury-free dental filling materials showed a bi-modal particle size distribution curve ranging from the nanometre to the micron scale. Scanning electron microscope images confirmed that particles are angular in shape. The acute immobilisation tests showed that, between the three clinics that were tested, different wastewater loads were produced depending on clinic and treatment type. Therefore, concentrations as low as 0.4 ml/L and as high as 40 mL/L of test substance (wastewater) have led to 100 % immobilisation. Conclusions This study shows that amalgam separators do not effectively remove all particles resulting from the use of mercury-free dental materials from the wastewater and depending on the treatment type, large volumes of particles of different size classes are released. While acute immobilisation tests confirmed toxicity of the wastewater at even low concentrations, further research needs to be undertaken to assess the environmental impacts.
Irish Division Meeting
2019 Irish Division Meeting (Cork, Ireland)
Cork, Ireland
2019

Accepted Abstracts
  • Binner, Hannah  ( School of Biological, Earth and Environmental Sciences )
  • Sullivan, Timothy  ( School of Biological, Earth and Environmental Sciences )
  • Hayes, Martina  ( Cork University Dental School and Hospital, University College Cork )
  • Environment Protection Agency (EPA): Assessment of the environment and health impacts arising from mercury-free dental restorative materials

    Irish Division Poster Presentation Session